A pure white world, everything being flat all the way to the orizon and even past that.
Though, it's not void nor is it empty, for it has atmospheric condictions simlar to earth, though without clouds oddly enough, and furthermore the dimension was filled with floating canvases, of all shapes and size, some tiny, some giagantic, depicting scenes of all sorts of things going from simple scenearies, to fierce battlefields, to even just peculiarly nice weddings, all captured there by presumebly the painter friends of theirs.
All of that is illuminated by a giant golden heart in the sky, it's light acting as the sun of that world and irradiating positive energy and warmth.
Oh, and there's also one white, red and black traditional japense-style tiny building just standing there, most lively Tangoku no Gaka's house.